Developing an Off-Grid Solar Power System
Over the past few months, much of the R&D at EYM has gone into the development of an off-grid PV solar power energy system. Actually, I did search for local solar installers/ professionals but they either did not service off-grid properties or were simply too busy. One company came to “give an estimate” and never answered our calls or emails. It was as if they went out of business. There is a lack of solar experts and shops where you can just ask common questions. There is a lot more to say on this topic of accessibility and know-how behind a more sustainable energy source but perhaps I can tell you more about it in person ;).
There are 3 key benefits of solar energy that we should keep in mind.
First, solar energy is a renewable resource that is environmentally friendly and sustainable. Second, using solar energy to power your grow lights can reduce your electricity bills and save you money in the long run. Finally, using solar energy can also allow you to grow microgreens in areas where electricity is not readily available, such as in remote locations or areas with unreliable power grids.
All in all, I have been aware of the many benefits of solar but never have had the ability to apply it until now. Talk about shifting gears to understand Ohm’s Law, load capacity, batteries, solar equipment and the various ways to install them and increase solar harvest yields.
Creating this solar system for me continues to challenge me in various ways, which is right in line with what Ryan Holiday writes, “to argue, to complain, or worse, to just give up, these are choices. Choices that more often than not, do nothing to get us across the finish line.” So instead of taking the perspective: “Why did this happen to me? Why me? Accept the challenge and now wish I would have started much earlier! Which complements growing microgreens perfectly!
But with so many things still on my plate, I would have preferred to focus on optimizing the verticalized microgreens production system or continue optimizing the upcycling shipping box project (more on this soon) but the need for Solar Power called! And now I am happy that it did! Because it’s a success and the microgreen powered by solar are self-sustaining!
Fortunately, I had time to do more research and compared various options for off-grid systems, while preventing anyone from electrocution or a fire. I was not alone in this; thus, I have plenty of people to thank, including Will Powers for his very clear and practical solar power knowledge via books and youtube videos. I also have had local help from neighbors, friends, and interns, who continue to amaze me with their creativity and engineered designs.
After researching various forums and options, we went with the proper solar setup that is currently providing the right amount of light for EYM’s new Basic & Spicy Micro Salad Mixes!
The design is currently meant to power one full rack of microgreens, with the following components summarized below:
- Solar Panels: We included four 100-watt solar panels, wired in series to produce a total of 400 watts of power. We choose these panels due to their durability and lightweight structure (can easily be confused as textile looking panels). The solar panels were mounted on a custom made structure, and raised with two posts to 2 meters, facing south. We also have already made the improvement of having a solar tilt since the first installation
- Mppt Charge Controller: A Maximum Power Point Tracking (MPPT) charge controller is a device that regulates the charging of a battery bank from a solar panel array. It is designed to maximize the power output of the solar panels and increase the efficiency of the charging process. We selected an MPPT with a 20-amp, which is suitable for a small to medium-sized solar power systems, as it can handle up to 20 amps of charging current and is capable of maximizing the power output of the solar panel array.
- Batteries: We went with two 12-volt AGM (Absorbent Glass Mat) deep cycle batteries with a capacity of 100Ah, which is needed to store the energy generated by the solar panels. These batteries are wired in parallel to increase the storage capacity and maintain a 12-volt output. AGM batteries are sealed, maintenance-free, and designed to deliver high performance and reliability.
- Inverter: An inverter is used to convert the 12-volt DC power from our two batteries into 220-volt AC power for use by our grow lights, fans, and a few electronics. We have installed a 2000-watt pure sine wave inverter which is more than enough energy output, with an expansion to the system in mind.
- Wiring and Fuses: Appropriate wiring and fuses have been used to connect all the components of the system together. The wiring would need to be sized appropriately to handle the current and voltage of the system, which has been one of the most difficult as wiring must be properly sized to handle the maximum current and voltage of the system. This involves calculating the wire gauge, length, and voltage drop based on the system's specifications and requirements.
- Monitoring (Battery & System): A battery monitor would be installed to track the battery voltage and charge level. This would help prevent over-discharging the batteries, which can damage them. There is a separate bluetooth battery monitoring device. However, to monitor the charge controller, we have installed a remote display to monitor the performance of our solar energy system and provide real-time information about the system’s status, including battery voltage, charging current, and solar panel output.
- Solar Frame and Tilt:
Last but not least is the installation of the solar panels. The recommendation is usually the roof due to its height and lack of obstruction (just make sure the roof is not facing north). Mike Li (HAS) and I decided to build a frame for the 4 panels, pointing south and with a solar tilt to adjust for the changing seasons. You can see our designs in the photos and even another improvement on the frame and solar monitoring system.
With this setup, there is enough power to grow microgreens indoors, which in May in the Netherlands seems to be the right situation. The next iteration will also include wind power as a combined energy source (still amazed that this is not flying off shelves here!)
Even though there is less sun than sunny SoCal, the system is self-sustaining on a small scale which is just another sustainable and great option for what a sustainable local food system can look like. “Grown Indoors with Solar Power” is in the works!